From the book : 'A tiling of interlocking figures such as circles, squares, or hexagons may lead the viewer’s eye from one to another figure. But after a while, the viewer’s focus tends to flip back and forth between them. This type of reverse tiling of interlocking figures is often found in Arabic ornamentation, such as in designs at the Alhambra, a fourteenth-century castle in Granada, Spain'. And I add my picture of the Alcazar in Seville...